1. Field of the Invention
The present invention relates to a photoresist composition, and more particularly, to a photoresist composition comprising fluoro-containing polymer.
2. Description of the Related Art
As the manufacture of semiconductor devices becomes more complex and semiconductor chips are more integrated, it is essential to form fine patterns in photolithography. Furthermore, as the capacity of a semiconductor memory device increases to exceed 4 Gigabit, a pattern size having a design rule less than 0.1 xcexcm is required. Accordingly, there are limitations to using a KrF excimer laser (248 nm wavelength) or an ArF excimer laser (193 nm wavelength) as the light source in photolithography. Thus, a new laser referred to as a xe2x80x9cF2 excimer laser (157 nm wavelength)xe2x80x9d has been introduced.
In general, a photosensitive polymer is used as photoresist material for the F2 excimer laser. The photoresist material should have characteristics of: (1) being transparent against 157 nm wavelength, (2) having high resistance to dry etching, (3) having excellent adhesion to a underlying layer and (4) being capable of being easily developed using a developer such as tetramethyl ammonium hydroxide (TMAH), which is very common in semiconductor manufacturing.
However, conventional photosensitive polymers have poor optical transparency at 157 nm wavelength. When the conventional photosensitive polymer is used for the photoresist material layer, the photoresist material is formed on an underlying layer with thickness of about 1,000 xc3x85, which is a much thinner thickness than normal thickness of the photoresist material. In this case, the photoresist material layer displays inadequate etch resistance and in some cases, can be defective because of a thinner thickness layer.
Thus, much research has been devoted to a photosensitive polymer suitable for use with a F2 excimer laser (157 nm wavelength), in which a fluorine is introduced to a photosensitive polymer. This polymer may be represented by the following chemical formula: 
The photosensitive polymer having maleic anhydride such as Chemical formula 1, may be easily made into a radical polymerization, and can improve on the adhesion characteristics with respect to an underlying layer. However, the photoresist material having maleic anhydride has poor optical transparency. The photoresist material having Chemical formula 2 has better optical transparency than the photoresist material having Chemical 1, but it has poor adhesion to an underlying layer because of hydrophobic characteristic.
Accordingly, it would be desirable to develop new photoresist materials, which have: (1) high optical transparent at a wavelength of 157 nm; (2) strong resistance to dry etching; and (3) excellent adhesiveness to a underlying layer.
A photosensitive polymer is provided which comprises: (a) perfluoro-2,2-dimethy-1,3-dioxol derivatives having the following repeating unit: 
and (b) vinyl derivatives having the following repeating unit: 
wherein R1 is H, Cl, or F; each of R2 and R3 is H or F; R4 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
According to the preferred embodiment of the present invention, R4 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3, the photosensitive polymer has a weight average molecular weight ranging from about 3,000 to about 200,000. Preferably, the photosensitive polymer has a weight average molecular weight ranging from about 4,000 to about 50,000.
A photosensitive polymer is provided which comprises: (a) perfluoro-2,2-dimethy-1,3-dioxol derivative having the following repeating unit: 
and (b) norbornen derivative having the following repeating unit: 
wherein R9 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
According to a preferred embodiment of the present invention, R9 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3. The photosensitive polymer has a weight average molecular weight ranging from about 3,000 to about 200,000. Preferably, the photosensitive polymer has a weight average molecular weight ranging from about 4,000 to about 50,000.
A photosensitive polymer is provided which comprises: (a) perfluoro-2,2-dimethy-1,3-dioxol derivative having the following repeating unit: 
(b) vinyl derivative having the following repeating unit: 
and (c) norbornen derivative having the following repeating unit: 
wherein R1 is H, Cl, or F; each of R2 and R3 is H or F; each of R4 and R9 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q includes perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
According to a preferred embodiment of the present invention, at least one of R4 and R9 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3. The photosensitive polymer has a weight average molecular weight ranging from about 3,000 to about 200,000. Preferably, the photosensitive polymer has a weight average molecular weight ranging from about 4,000 to about 50,000.
A photoresist compostion is also provided which comprises: (a) a photosensitive polymer comprsing: (a-1) perfluoro-2,2-dimethy-1,3-dioxol derivatives having the following repeating unit: 
and (a-2) at least one comonomer of a vinyl derivative having the following repeating unit: 
and a norbornen derivative having the following repeating unit: 
and (b) a photoacid generator (PAG),
wherein R1 is H, Cl, or F; each of R2 and R3 is H or F; each of R4 and R9 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
According to the preferred embodiment of the present invention, at least one of R4 and R9 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
According to an aspect of the invention, the photoresist composition includes from about 0.5 to about 20 weight percent of the photoacid generator based on the weight of the photosensitive polymer, and the photoacid generator is selected from the group consisting of triarylsulfonium salt, diaryliodonium salt, sulfonate, and the mixtures thereof.
According to an aspect of the invention, the photoresist composition further includes an organic bases in an amount of from about 10 to about 50 mole percent based on the mole of the photoacid generators. Preferably, the organic base is selected from the tertiary amine group and mixtures thereof.
The present invention now will be described more fully hereinafter with reference to the accompanying specification, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclose will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
The present invention relates to first photosensitive polymers comprising:
(a) perfluoro-2,2-dimethy-1,3-dioxol derivatives having the following repeating unit: 
and (b) vinyl derivatives having the following repeating unit: 
In the above formula, R1 is H, Cl, or F; each of R2 and R3 is H or F; R4 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
Preferably, R4 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
The photosensitive polymers may have various molecular weights. Preferably, the photosensitive polymers have weight average molecular weights ranging from about 3,000 to about 200,000. More preferably, the weight average molecular weights range from about 4,000 to about 50,000.
According to the present invention, the first photosensitive polymer is expressed by the following chemical formula: 
In the above formula, R4 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
Preferably, R4 is fluorinated alkyloxy group having an acid-labile group. More preferably, R4 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3. The ratio of k/(k+l) ranges from about 0.2 to about 0.7.
According to the present invention, the first photosensitive polymer also is expressed by the following chemical formula: 
In the above formula, each of R9 and R5 is H, Cl, or F; each of R2, R3 , R6 and R7 is H or F; each of R4 and R8 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon). At least one of R4 and R8 includes fluorinated alklyoxy group having an acid-labile group. The ratio of k/(k+l+m) ranges from about 0.1 to about 0.7; the ratio of l/(k+l+m) ranges from about 0.1 to about 0.6; and the ratio of m/(k+l+m) ranges from about 0.1 to about 0.6.
Preferably, at least one of R4 and R8 is fluorinated alkyloxy group having an acid-labile group. More preferably, at least one of R4 and R8 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
The present invention also relates to second photosensitive polymers comprising:
(a) perfluoro-2,2-dimethy-1,3-dioxol derivatives having the following repeating unit: 
and (b) norbornen derivatives having the following repeating unit: 
In the above formula, R9 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
Preferably, R9 is fluorinated alkyloxy group having an acid-labile group. More preferably, R9 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
The photosensitive polymers may have various molecular weights. Preferably, the photosensitive polymers have weight average molecular weights ranging from about 3,000 to about 200,000. More preferably, the weight average molecular weights range from about 4,000 to about 50,000.
According to a present invention, the second photosensitive polymer is expressed by the following chemical formula: 
In the above formula, R9 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon). The ratio of k/(k+n) ranges about from about 0.2 to about 0.7.
Preferably, R9 is fluorinated alkyloxy group having an acid-labile group. More preferably, R9 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
According to a present invention, the second photosensitive polymer is also expressed by the following chemical formula: 
In the above formula, each of R9 and R10 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon). At least one of R9 and R10 is fluorinated alklyoxy group having an acid-labile group. The ratio of k/(k+n+o) ranges from about 0.1 to about 0.7; the ratio of n/(k+n+o) ranges from about 0.1 to about 0.6; and the ratio of o/(k+n+o) ranges from about 0.1 to about 0.6.
Preferably, at least one of R9 and R10 is fluorinated alkyloxy group having an acid-labile group. More preferably, at least one of R9 and R10 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
The present invention also relates to third photosensitive polymer comprising:
(a) perfluoro-2,2-dimethy-1,3-dioxol derivatives having the following repeating unit: 
(b) vinyl derivatives having the following repeating unit: 
and (c) norbornen derivatives having the following repeating unit: 
In the above formula, R1 is H, Cl, or F; each of R2 and R3 is H or F; each of R4 and R9 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms in, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
Preferably, at least one of R4 and R9 is fluorinated alkyloxy group having an acid-labile group. More preferably, at least one of R4 and R9 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
The photosensitive polymers may have various molecular weights. Preferably, the photosensitive polymers have weight average molecular weights ranging from about 3,000 to about 200,000. More preferably, the weight average molecular weights range from about 4,000 to about 50,000.
According to a present invention, the third photosensitive polymer is expressed by the following chemical formula: 
The ratio of k/(k+l+n) ranges about from about 0.1 to about 0.7; the ratio of l/(k+l+n) ranges about from about 0.1 to about 0.6; and the ratio of n/(k+l+n) ranges about from about 0.1 to about 0.6.
The present invention also relates to photoresist compositions. The photoresist compositions comprise:
(a) photosensitive polymers comprising:
(a-1) perfluoro-2,2-dimethy-1,3-dioxol derivatives having the following repeating unit: 
and (a-2) at least one comonomer selected from consisting of vinyl derivatives having the following repeating unit: 
and norbornen derivatives having the following repeating unit: 
and (b) photoacid generator (PAG).
In the above formula, R1 is H, Cl, or F; each of R2 and R3 is H or F; each of R4 and R9 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
Preferably, at least one of R4 and R9 is fluorinated alkyloxy group having an acid-labile group. More preferably, at least one of R4 and R9 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
According to a present invention, if the comonomer is vinyl derivative, the photoresist composition is expressed by the following chemical formula: 
In the above formula, R1 is H, Cl, or F; each of R2 and R3 is H or F; R4 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
Preferably, R4 is fluorinated alkyloxy group having an acid-labile group. More preferably, R4 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
The ratio of k/(k+l) ranges from about 0.2 to about 0.7.
According to a present invention, if the comonomer is vinyl derivative, the photoresist composition is expressed by the following chemical formula: 
In the above formula, each of R1 and R5 is H, Cl, or F; each of R2, R3, R6, and R7 is H or F; each of R4 and R8 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
Preferably, at least one of R4 and R8 is fluorinated alkyloxy group having an acid-labile group. More preferably, at least one of R4 and R8 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
The ratio of k/(k+l+m) ranges from about 0.1 to about 0.7; the ratio of l/(k+l+m) ranges from about 0.1 to about 0.6; and the ratio of m/(k+l+m) ranges from about 0.1 to about 0.6.
According to a present invention, if the comonomer is nobornene derivative, the photoresist composition is expressed by the following chemical formula: 
In the above formula, R9 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
Preferably, R9 is fluorinated alkyloxy group having an acid-labile group. More preferably, R9 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
The ratio of k/(k+n) ranges from about 0.2 to about 0.7.
According to a present invention, if the comonomer is nobornene derivative, the photoresist composition is also expressed by the following chemical formula: 
In the above formula, each of R9 and R10 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms, ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms), or OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
Preferably, at least one of R9 and R10 is fluorinated alkyloxy group having an acid-labile group. More preferably, at least one of R9 and R10 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
The ratio of k/(k+n+o) ranges from about 0.1 to about 0.7; the ratio of n/(k+n+o) ranges from about 0.1 to about 0.6; and the ratio of o/(k+n+o) ranges from about 0.1 to about 0.6.
According to a present invention, if the comonomers are both vinyl derivative and nobornene derivative, the photoresist composition is also expressed by the following chemical formula: 
In the above formula, R1 is H, Cl, or F; each of R2 and R3 is H or F; each of R4 and R9 is H, F, CF3, OCF3, OCF2CF3, OCF2CF2CF3, CH2C(CF3)2OH, fluorinated alkyloxy group having an acid-labile group, n-perfluoroalkyl group having 1 to 8 carbon atoms; ORF (wherein RF is n-perfluoroalkyl group having 1 to 3 carbon atoms); OQZ (wherein Q is perfluorinated alkylene group having 0 to 5 oxygen atoms, the sum of carbon atom and oxygen atom in the Q is 2 to 10, and Z is COOR, SO2F, CN, COF, or OCH3, wherein R is alkyl group having 1 to 4 carbon).
Preferably, at least one of R4 and R9 is fluorinated alklyoxy group having an acid-labile group. More preferably, at least one of R4 and R9 is CH2C(CF3)2OCH2OCH3, CH2C(CF3)2OCH2OCH2CH3, CH2C(CF3)2OCH(CH3)OCH3, or CH2C(CF3)2OCH(CH3)OCH2CH3.
The ratio of k/(k+l+n) ranges from about 0.1 to about 0.7; the ratio of l/(k+l+n) ranges from about 0.1 to about 0.6; and the ratio of n/(k+l+n) ranges from about 0.1 to about 0.6.
The photosensitive polymers may have various molecular weights. Preferably, the photosensitive polymers have weight average molecular weights ranging from about 3,000 to about 200,000. More preferably, the weight average molecular weights range from about 4,000 to about 50,000.
Various photoacid generators may be used in the photoresist compositions. Preferably, the photoacid generators are selected from the group consisting of triarysulfonium salts, diaryl iodonium salts, sulfonates, and the mixtures thereof. More preferably, the photoacid generators are selected from group consisting of triphenyl sulfonium triflate, triphenyl sulfonium antimonate, diphenyl iodonium triflate, diphenyl iodonium antimonate, methoxy diphenyl iodonium triflate, di-t-butyl diphenyl iodonium triflate, 2,6-dinitrobenzyl sulfonates, pyrogallol tris(alkylsulfonates)), N-hydroxysuccin imide triflate, norbornene-dicarboximide-triflate, triphenyl sulfonium nonaflate, diphenyl iodonium nonaflate, methoxy diphenyl iodonium nonaflate, di-t-butyl diphenyl iodonium nonaflate, N-hydroxysuccin imide nonaflate, norbornene-dicarboximide-nonaflate, triphenyl sulfonium perfluorooctane sulfonate (PFOS), diphenyl iodonium PFOS, methoxy diphenyl iodonium PFOS, di-t-butyl diphenyl iodonium triflate, N-hydroxy succinimide PFOS, norbornene-dicarboximide PFOS, and the mixtures thereof.
Preferably, the photoresist compositions include from about 0.5 to about 20 weight percent of the photoacid generators based on the weight of the photosensitive polymers.
The photoresist compositions further comprise an organic bases in an amount of from about 10 to about 50 mole percent based on the mole of the photoacid generators. Preferably, the organic bases are selected from the tertiary amine group and mixtures thereof. More preferably, the organic bases are selected from group consisting of triethyl amine, triisobutyl amine, triisooctyl amine, triisodecyl amine, triethanol amine, N,N-dimethyl-1-naphthyl amine, N-cyclohexyl pyrrolidinone, N-cyclopentyl pyrrolidinone, N-pentyl pyrrolidinone, N-hexyl pyrrolidinone, N-allyl caprolactam, N-ethyl caprolactam, N-butyl caprolactam, N-propyl caprolactam, N-butyl valerolactam, N-isobutyl valerolactam, N-secbutyl valerolactam, and mixtures thereof.
The photoresist compositions according to a preferred embodiment of the present invention are transparent at 157 nm wavelength. Moreover, the etch resistance of the photoresist compositions is superior to conventional photoresist compositions. Also, lifting of photoresist films formed from photoresist compostions typically does not occur primary due to its excellent adhesiveness. Thus, the photoresist compositions using the photosensitive polymers according to the present invention produce a sharp photoresist pattern when exposed at a laser of 157 nm wavelength.
The following examples are set forth for illustrating the present invention, and are not to be interpreted as limiting thereof.